This invention relates to novel silicone compositions and more particularly to silicone compositions having improved spray flammability resistance.
In recent years the search for potential alternatives to the use of organic liquids whose environmental consequences are suspect, e.g. polychlorinated biphenyls, in such areas as hydraulic fluids, heat transfer fluids, transformer coolants, dielectric mediums, and the like, which are employed in closed equipment such as transformers, capacitors, and the like, has become increasingly important. Low viscosity poly(dimethylsiloxane) fluids have been proposed as an alternative liquid for such types of commercial applications. While such siloxane fluids are generally recognized as having low fire potential due to their chemical/thermal stability and high flask, fire and auto-ignition temperatures, low viscosity poly(dimethylsiloxane) fluids in the form of spray or atomized particles are combustible and such type of incineration is a commonly recommended means for their disposal. Thus, in applications where the low viscosity poly(dimethylsiloxane) fluid could be under pressure, such as in heat transfer, hydraulic, transformer, capacitor, or other closed equipment, and suddenly released there is a greater than normal fire potential if ignition sources are also present. For instance, the Factory Mutual's Spray Flammability Test is a commonly recognized test which simulates a potential fire hazard which might occur in the event of a line rupture carrying a fluid under pressure. Low viscosity poly(dimethylsiloxane) fluids per se have been found to burn vigorously by this test.